Two-stage compression-pump.



G. J. SPOHRER. Two-STAGE GOMPRBssmN PUMP.

APPLICATION FILED MAR. 9L 1912.

I manmfxs puritan sanare rant snip.,

GREGORY JOHN SPOHRER, F FRANKLIN, PENNSYLVANA, ASSGNOR T0 WILSON MOTORSTARTER COMPANY, 0F FRANKLIN, PENNSYLVANIA.

'llO-STAGE COMPRESSIONPUMP.

Specification o1 Letters Patent.

Application filed Ilarch', 1912. Serial No. 682,583.

To all 'whom it may concern Be 1t known that l, GREGORY J. Sron'nnn,

a citizen of the United States, and a resident of Franklin, in thecounty of Vcnango and State of Pennsylvania, have Ainvented a C new andImproved Two-Stage Compres-4 starting mechanism, tire-intlatingmechanism. etc. The pumps now on the market -are objectionable, because,among other reasons, they occupy a large amount of valuable space, andwith pistons oi small diameter, especially the high pressure piston ot asmall two-stage compression pump suilh cient area ot bearing cannot beobtained by the usual wrist pin or piston bearing to substantially standthe strain and wear. lt is understood in pump constructions that a lowpressure cylinder must be of relatively great diameter compared with thehigh pressure cylinder, in order to obtain an economical ratio ofcompression, and in those pumps, the strokes in both the high and thelow pressure cylinders are equal, the only change being made in thedia1neter of the cylinders in which the compression takes place. l l 1 Iconstruct a two-stage compression pump particularly adapted forautomobile use, in which the low pressure cylinder is more nearly equalto the dimensions otl the high pressure cylinder, and obtain thenecessary ratio of cylinder volume by varying the eX- tent ofreciprocation of the pistons, by positioning the pins in the crankshafts difierent distancesiirom the axis of rotation of the actuatingshaft. kTo `further economize 'the space occupied by such a pump, l makethe crank link relatively short and it is a desideratum in a device ofthis character, to shorten 'the length of the piston, but as Ithispiston must work against heavy pressure', it is necessary that it be ofsufficient rigidity and size to withstand this pressure. The connectionsat present used in devices of this character are not adapted to form astrong` connect-ion between a relatively short piston and a relativelyshort link. It is advisable to have this connection positioned wellwithin the body of the piston, and this form of connection always formsa 'feature of my invention, and in the present instance, I make use outa hellend-socket connection which gives' a firm connection in arelatively small piston, presenting more bearing surface and allowingthe center of swing to be brought well up within the top of the piston.These two- ;teatures are not allowable in present forms of pistonbearings, l further increase the space for bearing in the high pressurepiston by shortening the relative stroke of the high to the low, therebyincreasiiig the diameter oi' the high pressure cylinder and. stillmaintaining` the proper cylinder volume essential to two stagecompressiom the whole device forming a small compact pump of higheihciency.

Reference is to be hadjto the accompany- :carentes aan is, isis.,

ing drawings, forming a 'part of this specitlcation, in which the ligureis a vertical transverse sectional view taken through a simple form 'ofpump. As is general in constructions of this na ture, there is provideda shell A, the upper portion of which is formed into a low pressurecylinder B and a high pressure cylinder C, in each of which cylinders isdisposed a piston D, said piston being connected byn means oit aconnecting rod E to a crank F mounted in a driving shaft G, The fluid tobe compressed is admitted through the inlet H and forced through thevalve-covered outlet I and through the passage J into the high pressurecylinder C, ythe, piston in which cylinder, on its return stroke forcesthe compressed gas through the valve-con trolled outlet K. It will benoted thatfthe high pressure cylinder C is almost the diameter of thelow pressure cylinder B, and, it desired, both ot' these cylinders mightbe ot the same volume.

The link connections with the pistons aie` relatively short, and thedevice is so coni structed that the pistons approach as closely aspossible-'to the shaft G at one limit of their stroke, soA as tomaintain the height of the pump'as small as possible. The ratio ofstroke between the high and the low pressure cylinders is obtained byvarying the distance of the crank pins L from the axis and the pin ofthe low pressurecylin-4 der. In other words, I reduce the ratiobeportion of the sphere.

tween the cylinder diameters and change the ratio of the strokes of the'pistons in the cylinders, by means of a pair of unequal double cranks.The pistons in this case are substantially hollow cylinders, thecompression end of each .of which is closed and the end facing the crankopen. Within the open end and preferably a short distance fromthecompression end, is a semi-spherical recess 2, freely revoluble inwhich recess is a sphere 3, extending diametrically within the vlowerside of which is a screw-v threaded bore 4,v which is engaged by areduced threaded end 5 of the connecting rod E.

In the case of the high pressure piston, the sphere 3 is retained inposition by means of an exteriorly threaded sleeve 6, the upper end ofwhich has a. spherical recess 7 adapted to. engage the under side of thesphere, said sleeve being in screw-threaded engagement with the openendof the piston. In the case of the low pressure piston, a hollow bearingblock 8 may be interposed between the sleeve 6 and the s here 3. Thislatter construction is prefere le and is possible in the case of the lowpressure piston, due to the larger size of 'this piston, therebyaffording space in which to introduce this bearing block. 'It is tobe'understood that the bearing block has its recess' ground to conformto` the onguration of the lower The connecting rod E projects throughthe sleeve 6, the opening through this sleeve being in the form of thefrustum of a cone,

in order to permit the swinging of the connecting rod. Suitable packing9 is carried by the compression end of the piston, preventing theleakage of the Huid about the piston.' L

From the construction illustrated it will ap' ear that the compressionends ofthe cylin ers B and C lie in substantiallythe same plane wherebycommunication from one to the other is most conveniently arranged, afact in harmony also with the general comactness of the entireeonstuction It will e noted also that notwithstanding the dif-v ing rodsE are or may be duplicates of each other, and hence interchangeable, anelement of vast importance commercially. It followstherefore, because ofthe foregoing facts, that the lengths of the pistons from theircompression ends to the centers of th'e respective balls 3 are very.different, the length of the high pressure piston being greater thanthe other. This provides .ample space for the ap )lication of thepacking/9 thereto without interference with thel ball and socketconstruction. Since the strokes of the two pistons are different inextent, but being operated by the same crank shaft, the low pressurepiston must o erate at a considerably hi her speed than at of the highpressure cy inder, and henc: while the low pressure piston is making itscompression stroke there will be a continuous compression of the gas asit flows into the compression chamber of the high pressure cylinder, byreason of the .fact that the high pressure piston is receding therefromat a comparatively low rate of speed. The maximum pressure therefore ishad at the momentl the low pressure piston reaches its maximumcompression stroke. In other words, at no time from the beginning 'ofthecompression stroke of the low pressurey piston is there any possibilityof expansion of the gas vand a resulting loss of force thereof.

l'Vhile the novel elements have been described withvreference to apump," it is, of course, to be understood thatA these new features maybe utilized with obvious mechanical variations, to adapt the device toengines, 'meters, or, in fact, any place where a reciprocating member isdriven from a crank shaft. e

Having thus described my invention, I claim as new and desireto secureby Letters Patent: u

l.' In a two-stage compression pump, the combination of a pairofcylinders having a valved communication from one to the other,

pistons inthe respectivecylinders, a crank shaft, connecting rodsconnected to the pistons, and a pair of cranks of unequal lengthsoperatively connecting said connecting rods with the crank shaft wherebythe -pistons are driven at different rates of speed Vand given unequalstrokes.

2. The herein described `two-stage compression pump comprising a pair ofcylinders extending at' their compression ends to the same plane and ofdifferent diameters, pistons of diiierent diameters fitted in saidcylinders and adapted to reach said plane in their successivecompression strokes, connecting rods for the pistons, the connecting rodfor the larger piston being connected thereto adjacent the compressionend of the piston, `and the connecting rod for the other www@ pistonbeing connected thereto at a point remote from the compression end, acrank shaft, and means connecting the connecting rods to theshaftwhereby the pistons are operatedsimultaneously lfrom said crank shaft inopposite directions at diercnt rates of speed. v

n testimony whereof have-signed my neme to this specification in thepresence of two subscribing'witiicsses.

GREGORY JOHN SFOHRER. 1Witnesses:

HOMER R. BLAIR, HOLLY E. 'HOOVER

